WASHINGTON -- Federal prosecutors and defense attorneys made good on long-standing promises Wednesday that the perjury trial of baseball great Roger Clemens will hinge largely on the credibility of the pitcher's former trainer who the government said collected potentially devastating evidence of Clemens' drug use and who defense lawyers castigated as a serial "liar.''

In opening statements in the case where Clemens is accused of lying to Congress when he emphatically denied using performance enhancing drugs, Brian McNamee, who helped train Clemens for nearly a decade and alleges that he injected Clemens numerous times with banned substances, quickly assumed the role as the trial's central figure.

Through McNamee and other witnesses, including convicted drug dealer Kirk Radomski, prosecutors promised to provide jurors evidence of Clemens' use of performance hancing drugs down to the "dates, times, locations and sources'' of illegal steroids and human growth hormone.

For the first time, prosecutor Steven Durham also told the packed courtroom that Clemens' DNA had been linked to used needles and bloody cotton swabs that were tainted with anabolic steroids.

Flashing photographs of a fit Clemens in a New York Yankee uniform and of the used needles and soiled gauze that McNamee allegedly scavanged from the pitcher's New York apartment a decade ago, Durham said the government would prove every "false statement'' uttered by the defendant.

Durham said the government would also produce the man who provided the drugs to Clemens. The prosecutor said that man, Radomski, a former clubhouse attendant for the New York Mets, sent a package containing human growth hormone to Clemens' Houston home in 2003.

"That person will walk into this courtroom; he will walk right past you,'' Durham said, referring jurors to Radomski's path to the witness stand. "Radomski,'' Durham said, before whirling to point at Clemens seated at the nearby defense table, "sent a package of HGH to this man's house.''

Clemens, dressed in a dark suit, showed no reaction, as a mailing label from the package bearing the defendant's address was flashed on a courtroom screen. In statements to Congress and public comments to reporters, Clemens has denied using performance enhancing drugs of any kind. He said the only shots he received from McNamee were injections of the vitamin B-12 and the pain reliever lidocaine.

Radomski, Durham said, would be one of 45 witnesses for the prosecution. And Durham said some of those witnesses would include those who would corroborate McNamee's accounts that Clemens used performance enhancing drugs, including Clemens' former teammate and friend Andy Pettitte.

"We're not simply going to ask you to hang your hat on everything Mr. McNamee says,'' Durham told the jury.

But Clemens' defense attorney, Rusty Hardin, made it clear that the government's case would succeed or fail on McNamee's credibility.

"Brian McNamee, to put it delicately, is a liar,'' Hardin said. "He lied before this started, he's lied during it. He's still lying.''

Hardin suggested that McNamee "created'' the medical waste that allegedly links Clemens to steroids. The defense attorney also signaled that the defense would challenge when the tainted needles and swabs were collected and how they were stored before the material was turned over to the government in 2008.

Displaying a timeline of Clemens' life and baseball career, featuring photographs of the pitcher as a young boy and later as a star for the University of Texas, Hardin said it was Clemens' unusual "work ethic' -- not drugs -- that made him the successful professional athlete he became.

"Roger Clemens,'' Hardin said, "had the most tremendous work ethic anybody's ever seen.'' Hardin said defense witnesses will testify to Clemens' devotion to fitness, from the time he was an aspiring high school pitcher. At that time, he said Clemens used to spend many Friday nights alone sprinting across the baseball field with heavy weights strapped to his chest.

"Friends used to think he was crazy,'' Hardin said.

On the professional level, Hardin said Clemens enjoyed success well before and after his relationship with McNamee had ended. McNamee has alleged that Clemens' use of drugs began in 1998 and ended in 2001. But Hardin said some of Clemens' greatest accomplishments were earned before and after that period, including in 2004 when Clemens won his seventh Cy Young Award, recognizing baseball's best pitcher.

"It had nothing to do with steroids,'' Hardin said.

Continuing his attack on McNamee, Hardin suggested the government witness conspired with investigators to implicate Clemens while McNamee was training the pitcher.

"We used to have a phrase in Houston,'' Hardin said, referring to the days of the NFL's Houston Oilers: "All roads to the Super Bowl go through Pittsburgh. In this case, all roads go through Brian McNamee. Roger Clemens' only crime is having the poor judgment of staying connected with Brian McNamee.''

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